Search Results for author: Fabrizio Silvestri

Found 46 papers, 17 papers with code

$\nabla τ$: Gradient-based and Task-Agnostic machine Unlearning

no code implementations21 Mar 2024 Daniel Trippa, Cesare Campagnano, Maria Sofia Bucarelli, Gabriele Tolomei, Fabrizio Silvestri

In this study, we introduce Gradient-based and Task-Agnostic machine Unlearning ($\nabla \tau$), an optimization framework designed to remove the influence of a subset of training data efficiently.

Inference Attack Machine Unlearning +1

Link Prediction under Heterophily: A Physics-Inspired Graph Neural Network Approach

no code implementations22 Feb 2024 Andrea Giuseppe Di Francesco, Francesco Caso, Maria Sofia Bucarelli, Fabrizio Silvestri

Physics-Inspired GNNs such as GRAFF provided a significant contribution to enhance node classification performance under heterophily, thanks to the adoption of physics biases in the message-passing.

Link Prediction Node Classification +1

A topological description of loss surfaces based on Betti Numbers

no code implementations8 Jan 2024 Maria Sofia Bucarelli, Giuseppe Alessio D'Inverno, Monica Bianchini, Franco Scarselli, Fabrizio Silvestri

In the context of deep learning models, attention has recently been paid to studying the surface of the loss function in order to better understand training with methods based on gradient descent.

Community Membership Hiding as Counterfactual Graph Search via Deep Reinforcement Learning

no code implementations13 Oct 2023 Andrea Bernini, Fabrizio Silvestri, Gabriele Tolomei

Community detection techniques are useful tools for social media platforms to discover tightly connected groups of users who share common interests.

Community Detection counterfactual +1

RRAML: Reinforced Retrieval Augmented Machine Learning

no code implementations24 Jul 2023 Andrea Bacciu, Florin Cuconasu, Federico Siciliano, Fabrizio Silvestri, Nicola Tonellotto, Giovanni Trappolini

The emergence of large language models (LLMs) has revolutionized machine learning and related fields, showcasing remarkable abilities in comprehending, generating, and manipulating human language.

Retrieval

Investigating the Robustness of Sequential Recommender Systems Against Training Data Perturbations

no code implementations24 Jul 2023 Filippo Betello, Federico Siciliano, Pushkar Mishra, Fabrizio Silvestri

However, their robustness in the face of perturbations in training data remains a largely understudied yet critical issue.

Recommendation Systems

Renormalized Graph Neural Networks

no code implementations1 Jun 2023 Francesco Caso, Giovanni Trappolini, Andrea Bacciu, Pietro Liò, Fabrizio Silvestri

It is recognized as the preferred lens through which to study complex systems, offering a framework that can untangle their intricate dynamics.

Integrating Item Relevance in Training Loss for Sequential Recommender Systems

no code implementations18 May 2023 Andrea Bacciu, Federico Siciliano, Nicola Tonellotto, Fabrizio Silvestri

Sequential Recommender Systems (SRSs) are a popular type of recommender system that learns from a user's history to predict the next item they are likely to interact with.

Recommendation Systems

Multimodal Neural Databases

1 code implementation2 May 2023 Giovanni Trappolini, Andrea Santilli, Emanuele Rodolà, Alon Halevy, Fabrizio Silvestri

The rise in loosely-structured data available through text, images, and other modalities has called for new ways of querying them.

Information Retrieval Multimodal Deep Learning +1

The Dark Side of Explanations: Poisoning Recommender Systems with Counterfactual Examples

no code implementations30 Apr 2023 Ziheng Chen, Fabrizio Silvestri, Jia Wang, Yongfeng Zhang, Gabriele Tolomei

By reversing the learning process of the recommendation model, we thus develop a proficient greedy algorithm to generate fabricated user profiles and their associated interaction records for the aforementioned surrogate model.

counterfactual Counterfactual Explanation +4

Sheaf4Rec: Sheaf Neural Networks for Graph-based Recommender Systems

1 code implementation7 Apr 2023 Antonio Purificato, Giulia Cassarà, Federico Siciliano, Pietro Liò, Fabrizio Silvestri

GNNs have proven to be effective in addressing the challenges posed by recommendation systems by efficiently modeling graphs in which nodes represent users or items and edges denote preference relationships.

Collaborative Filtering Link Prediction +1

Combining Distance to Class Centroids and Outlier Discounting for Improved Learning with Noisy Labels

1 code implementation16 Mar 2023 Farooq Ahmad Wani, Maria Sofia Bucarelli, Fabrizio Silvestri

In this paper, we propose a new approach for addressing the challenge of training machine learning models in the presence of noisy labels.

Learning with noisy labels

Attention-likelihood relationship in transformers

1 code implementation15 Mar 2023 Valeria Ruscio, Valentino Maiorca, Fabrizio Silvestri

We analyze how large language models (LLMs) represent out-of-context words, investigating their reliance on the given context to capture their semantics.

Sparse Vicious Attacks on Graph Neural Networks

1 code implementation20 Sep 2022 Giovanni Trappolini, Valentino Maiorca, Silvio Severino, Emanuele Rodolà, Fabrizio Silvestri, Gabriele Tolomei

In this work, we focus on a specific, white-box attack to GNN-based link prediction models, where a malicious node aims to appear in the list of recommended nodes for a given target victim.

Link Prediction Recommendation Systems

GREASE: Generate Factual and Counterfactual Explanations for GNN-based Recommendations

no code implementations4 Aug 2022 Ziheng Chen, Fabrizio Silvestri, Jia Wang, Yongfeng Zhang, Zhenhua Huang, Hongshik Ahn, Gabriele Tolomei

Although powerful, it is very difficult for a GNN-based recommender system to attach tangible explanations of why a specific item ends up in the list of suggestions for a given user.

counterfactual Graph Classification +1

Detecting and Understanding Harmful Memes: A Survey

1 code implementation9 May 2022 Shivam Sharma, Firoj Alam, Md. Shad Akhtar, Dimitar Dimitrov, Giovanni Da San Martino, Hamed Firooz, Alon Halevy, Fabrizio Silvestri, Preslav Nakov, Tanmoy Chakraborty

One interesting finding is that many types of harmful memes are not really studied, e. g., such featuring self-harm and extremism, partly due to the lack of suitable datasets.

ReLAX: Reinforcement Learning Agent eXplainer for Arbitrary Predictive Models

1 code implementation22 Oct 2021 Ziheng Chen, Fabrizio Silvestri, Jia Wang, He Zhu, Hongshik Ahn, Gabriele Tolomei

However, existing CF generation methods either exploit the internals of specific models or depend on each sample's neighborhood, thus they are hard to generalize for complex models and inefficient for large datasets.

counterfactual Decision Making +2

Detecting Propaganda Techniques in Memes

1 code implementation ACL 2021 Dimitar Dimitrov, Bishr Bin Ali, Shaden Shaar, Firoj Alam, Fabrizio Silvestri, Hamed Firooz, Preslav Nakov, Giovanni Da San Martino

We further create and release a new corpus of 950 memes, carefully annotated with 22 propaganda techniques, which can appear in the text, in the image, or in both.

Database Reasoning Over Text

1 code implementation ACL 2021 James Thorne, Majid Yazdani, Marzieh Saeidi, Fabrizio Silvestri, Sebastian Riedel, Alon Halevy

Neural models have shown impressive performance gains in answering queries from natural language text.

SemEval-2021 Task 6: Detection of Persuasion Techniques in Texts and Images

1 code implementation SEMEVAL 2021 Dimitar Dimitrov, Bishr Bin Ali, Shaden Shaar, Firoj Alam, Fabrizio Silvestri, Hamed Firooz, Preslav Nakov, Giovanni Da San Martino

We describe SemEval-2021 task 6 on Detection of Persuasion Techniques in Texts and Images: the data, the annotation guidelines, the evaluation setup, the results, and the participating systems.

CycleDRUMS: Automatic Drum Arrangement For Bass Lines Using CycleGAN

no code implementations1 Apr 2021 Giorgio Barnabò, Giovanni Trappolini, Lorenzo Lastilla, Cesare Campagnano, Angela Fan, Fabio Petroni, Fabrizio Silvestri

The two main research threads in computer-based music generation are: the construction of autonomous music-making systems, and the design of computer-based environments to assist musicians.

Image-to-Image Translation Music Generation +2

CF-GNNExplainer: Counterfactual Explanations for Graph Neural Networks

1 code implementation5 Feb 2021 Ana Lucic, Maartje ter Hoeve, Gabriele Tolomei, Maarten de Rijke, Fabrizio Silvestri

In this work, we propose a method for generating CF explanations for GNNs: the minimal perturbation to the input (graph) data such that the prediction changes.

counterfactual

Neural Databases

no code implementations14 Oct 2020 James Thorne, Majid Yazdani, Marzieh Saeidi, Fabrizio Silvestri, Sebastian Riedel, Alon Halevy

We describe NeuralDB, a database system with no pre-defined schema, in which updates and queries are given in natural language.

Management

Interpretable Predictions of Tree-based Ensembles via Actionable Feature Tweaking

3 code implementations20 Jun 2017 Gabriele Tolomei, Fabrizio Silvestri, Andrew Haines, Mounia Lalmas

There are many circumstances however where it is important to understand (i) why a model outputs a certain prediction on a given instance, (ii) which adjustable features of that instance should be modified, and finally (iii) how to alter such a prediction when the mutated instance is input back to the model.

Feature Engineering

Scalable Semantic Matching of Queries to Ads in Sponsored Search Advertising

no code implementations7 Jul 2016 Mihajlo Grbovic, Nemanja Djuric, Vladan Radosavljevic, Fabrizio Silvestri, Ricardo Baeza-Yates, Andrew Feng, Erik Ordentlich, Lee Yang, Gavin Owens

For this reason search engines often provide a service of advanced matching, which automatically finds additional relevant queries for advertisers to bid on.

Neighborhood Sensitive Mapping for Zero-Shot Classification using Independently Learned Semantic Embeddings

no code implementations26 May 2016 Gaurav Singh, Fabrizio Silvestri, John Shawe-Taylor

In a traditional setting, classifiers are trained to approximate a target function $f:X \rightarrow Y$ where at least a sample for each $y \in Y$ is presented to the training algorithm.

General Classification Zero-Shot Learning

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